Emily, this is normal. And it will pass.
Memories of the past can stir up gender dysphoria, especially when brought up with people from before your transition, who may not be gendering you correctly in the present, if not explicitly through names and pronouns, then implicitly, through the subtle cues of interpersonal interaction.
But here's the thing: if you are female in spirit now, perhaps you have always been female in spirit? In which case, there was never a pre-transition self. It was always just you. So be aware that your memories may be... faulty. Incorrect. Just like your body, and the perception of it by all the people around you. You are not your memories.
And, actually, memories can change. Remind yourself that you've always been a woman... except when you were only a little girl. Actively let your current sense of self go back into those past memories. It can feel a bit like... time travel... especially if you encounter a memory of a future visitation from yourself.